Final answer:
The described study with carefully screened participants and random assignments to control or treatment groups refers to a controlled experiment in cognitive therapy for depression.
Step-by-step explanation:
The question appears to describe the methodology for an empirical study concerning the treatment of depression using cognitive therapy. The student details that participants are carefully screened, fit strict diagnostic criteria, and are randomly assigned to treatment or control groups. This type of methodology indicates that the study is likely a controlled experiment, which focuses on establishing causality by manipulating an independent variable and observing the effect on a dependent variable, while controlling other potential variables.
In the context of the given study, the experimental group would receive the actual cognitive therapy, whereas the control group would not receive the therapy or may receive a placebo treatment. By comparing outcomes between these two groups, the researchers aim to determine if cognitive therapy has a significant effect on treating depression.
It is important to remember that experimental designs also need to adhere to ethical standards. For example, experiments cannot expose participants to harm or coerce participation, and typically require informed consent from all participants.